Frequency Discrimination In Noise Research Articles

The role of efferents in human auditory development: efferent inhibition predicts frequency discrimination in noise for children.

The descending corticofugal fibers originate from the auditory cortex and exert control on the periphery via the olivocochlear efferents. Medial efferents are thought to enhance the discriminability of transient sounds in background noise. In addition, the observation of deleterious long-term effects of efferent sectioning on the response properties of auditory nerve fibers in neonatal cats supports an efferent-mediated control of normal development. However, the role of the efferent system in human hearing remains unclear. The objective of the present study was to test the hypothesis that the medial efferents are involved in the development of frequency discrimination in noise. The hypothesis was examined with a combined behavioral and physiological approach. Frequency discrimination in noise and efferent inhibition were measured in 5- to 12-yr-old children (n = 127) and young adults (n = 37). Medial efferent strength was noninvasively assayed with a rigorous otoacoustic emission protocol. Results revealed an age-mediated relationship between efferent inhibition and frequency discrimination in noise. Efferent inhibition strongly predicted frequency discrimination in noise for younger children (5-9 yr). However, for older children (>9 yr) and adults, efferent inhibition was not related to frequency discrimination in noise. These findings support the role of efferents in the development of hearing-in-noise in humans; specifically, younger children compared with older children and adults are relatively more dependent on efferent inhibition for extracting relevant cues in noise. Additionally, the present findings caution against postulating an oversimplified relationship between efferent inhibition and measures of auditory perception in humans.NEW & NOTEWORTHY Despite several decades of research, the functional role of medial olivocochlear efferents in humans remains controversial and is thought to be insignificant. Here it is shown that medial efferent inhibition strongly predicts frequency discrimination in noise for younger children but not for older children and adults. Young children are relatively more dependent on the efferent system for listening-in-noise. This study highlights the role of the efferent system in hearing-in-noise during childhood development.

Frequency discrimination in noise by untrained listeners

The frequency discrimination performance of adults, with no prior experience as listeners in psychoacoustic experiments, was examined for tones of 1000 and 4000 Hz presented in a background of broadband noise. The tones were presented at a signal‐to‐noise ratio expected to produce 80% correct detection. The level of the stimuli was either 45 or 60 dB SPL. The subjects were tested in a procedure similar to one used in infant psychoacoustics [Olsho et al., Devel. Psychol. 23, 627–640 (1987)]. Threshold values of Δf were found to be more similar to those of well‐trained listeners at 4000 Hz than at 1000 Hz. The effects of stimulus level were similar to those reported by Dye and Hafter [ 1748–53 (1980)] for well‐trained listeners: Threshold Δf increased with increasing level at 4000 Hz, but not at 1000 Hz. This result suggests that the effects of level on frequency discrimination in noise are robust enough to be replicated in subjects with little listening experience. Further, the effects of level on human in...

The effect of signal duration on frequency discrimination at low signal-to-noise ratios in different conditions of interaural phase

Frequency discrimination in noise at low signal-to-noise ratios where the signals to be discriminated are equally well detected but only faintly audible is better when the signals are in-phase at the ears than when they are out-of-phase. In spite of the difference in discriminability, however, the form of the dependence of the just-noticeable frequency difference on signal duration is the same in both cases.

Cognitive factors in masked frequency discrimination

Frequency discrimination in noise, using signals lying either within a critical band or within different critical bands, presents a paradigm to examine the question of serial versus parallel processing of incoming sensory stimuli. Three observers, two musically naive and one musically trained, were tested for frequency discrimination using a two-interval forced-choice procedure. Equally detectable 100-msec tonal signals, masked by continuous broad-band noise, appeared in each of the two intervals. One tone was always 500 Hz while the other was 500 Hz plus Δf, and observers were required to indicate which interval contained the higher frequency. Eight Δf's were used, ranging from 6.3 to 1636 Hz. For the musically naive observers, the percentage of correct responses [P(c)] improved with increasing Δf until a plateau was reached at a Δf of 25 Hz. This was true for both moderately [P(c) = 70%] and highly [P(c) = 90%] detectable signals. In both cases, asymptotic performance was at a percent correct corresponding to the detectability of either tone alone. This result suggests serial processing, since the listeners appeared unable to monitor simultaneously the output of two critical bands during the duration of the signal. The musically trained observed also showed asymptotic performance, but at a P(c) higher than that for detection alone. This latter result suggests a parallel process. These data differ from those of a previous study by Tanner [J. Acoust. Soc. Am. 28, 882–888 (1956)], where all subjects could be said to be serial processors, and as such this may reflect differences between the ways in which musicians and nonmusicians process frequencies. [Supported in part by grants from the National Institutes of Health and from Oberlin College.]

Frequency Discrimination in Noise

Frequency DLs were obtained near masked threshold (1–15 dB SL) at 250, 1000, and 4000 Hz. Three spectrum levels (31.5, 51.5, and 71.5 dB) were used. An adaptive sequential procedure based on 4IFC was used in estimating ΔF. Also, two signal modes were used. In one, the pulsed tone presented during the “signal interval” was frequency modulated. In the other, the pulsed tone presented during the “signal interval” was a steady, but different, frequency. Characteristic improvement was seen at all frequencies when ΔF was plotted as a function of sensation level. At 4000 Hz, however, a significant “noise-level” effect was noted, in which discrimination at the 51.5-dB spectrum level (band level of 86 dB) was poorer than that for 31.5 and 71.5 dB. This “noise-level” effect was essentially the same for both modes of signal presentation. While this effect is difficult to explain in psychophysical terms, the literature on physiological acoustics offers some promise of accounting for it.

Frequency Discrimination in Noise

Frequency DL's at 1000 Hz were obtained in quiet and at three noise levels—60, 80, and 100 dB SPL. Sensation levels of 4, 6, and 10 dB SL were used at each noise level. The DL's were obtained by means of a tracking task in which the subject controlled the input voltage to a frequency modulator. Characteristic improvement is seen when frequency DL's are plotted as a function of sensation level. The curve for the DL's for 60-dB SPL noise runs parallel to the curve for quiet, with the noise DL's slightly greater. The curves for the DL's for the 80- and 100-dB SPL noises are less steep, and the average DL's are greater than the DL's for quiet by ratios of 1.5:1 and 2:1, respectively. [This research was supported by research grants from the National Institute of Neurological Diseases and Blindness, U. S. Public Health Service.]

Sone relationships to stimulus discrimination in noise.

sone relationships to stimulus discrimination in noise.J H Dewson 3rd, and Efferent OLIVOCOCHLEAR BUNDJ H Dewson 3rd, and Efferent OLIVOCOCHLEAR BUNDPublished Online:01 Jan 1968https://doi.org/10.1152/jn.1968.31.1.122MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Download PDF FiguresReferencesRelatedInformation Cited ByThe role of the medial olivocochlear reflex in psychophysical masking and intensity resolution in humans: a reviewSkyler G. Jennings8 June 2021 | Journal of Neurophysiology, Vol. 125, No. 6The role of efferents in human auditory development: efferent inhibition predicts frequency discrimination in noise for childrenSrikanta K. Mishra16 June 2020 | Journal of Neurophysiology, Vol. 123, No. 6Adversarial relationship between combined medial olivocochlear (MOC) and middle-ear-muscle (MEM) reflexes and alarm-in-noise detection thresholds under negative signal-to-noise ratios (SNRs)Hearing Research, Vol. 367Morphofunctional alterations in the olivocochlear efferent system of the genetic audiogenic seizure-prone hamster GASH:SalEpilepsy & Behavior, Vol. 71Modulation of Auditory Signal-to-Noise Ratios by Efferent StimulationSeth M. Tomchik, and Zhongmin Lu1 June 2006 | Journal of Neurophysiology, Vol. 95, No. 6Mouse homolog of KIAA0143 protein: hearing deficit induces specific changes of expression in auditory brainstem neuronsMolecular Brain Research, Vol. 128, No. 2Anatomy of olivocochlear neurons in the hamster studied with FluoroGoldHearing Research, Vol. 185, No. 1-2Multiparametric corticofugal modulation and plasticity in the auditory system1 October 2003 | Nature Reviews Neuroscience, Vol. 4, No. 10Medial olivocochlear bundle activation and perceived auditory intensity in humansPhysiology & Behavior, Vol. 77, No. 2-3Behavioral investigation of some possible effects of the central olivocochlear pathways in transgenic miceHearing Research, Vol. 171, No. 1-2The effect of vestibular nerve section upon tinnitusClinical Otolaryngology and Allied Sciences, Vol. 27, No. 4Single Olivocochlear Neurons in the Guinea Pig. I. Binaural Facilitation of Responses to High-Level NoiseM. C. Brown, S. G. Kujawa, and M. L. Duca1 June 1998 | Journal of Neurophysiology, Vol. 79, No. 6Auditory efferents involved in speech-in-noise intelligibilityNeuroReport, Vol. 8, No. 7Single-unit recording in the ventral cochlear nucleus of behaving catsJournal of Neuroscience Methods, Vol. 40, No. 2-3Selective degeneration of a putative cholinergic pathway in the chinchilla cochlea following infusion with ethylcholine aziridinium ionBrain Research, Vol. 544, No. 1Selective damage to cochlear efferents by the choline neurotoxin ethylcholine mustard aziridinium ion (AF64A) in the chinchillaHearing Research, Vol. 42, No. 1Effect of noise masking on the brain-stem and middle-latency auditory evoked potentials: central and peripheral componentsElectroencephalography and Clinical Neurophysiology/Evoked Potentials Section, Vol. 74, No. 2Modulation transfer function of efferent neurones in the guinea pig cochleaHearing Research, Vol. 36, No. 1Efferent tracts and cochlear frequency selectivityHearing Research, Vol. 24, No. 3Crossed cochlear influences on monaural temporary threshold shiftsHearing Research, Vol. 9, No. 3Temporary threshold shift modified by binaural acoustic stimulationHearing Research, Vol. 6, No. 2Sectioning the efferent bundle decreases cochlear frequency selectivityNeuroscience Letters, Vol. 28, No. 1Efferent Components of the Auditory System4 December 2016 | Annals of Otology, Rhinology & Laryngology, Vol. 89, No. 5_supplOlivocochlear Bundle Activity Recorded in Awake Cats22 April 2016 | Otolaryngology-Head and Neck Surgery, Vol. 87, No. 4Auditory nerve fiber activity influenced by contralateral ear sound stimulationExperimental Neurology, Vol. 59, No. 1Effects of visual attention on tone burst evoked auditory potentialsExperimental Neurology, Vol. 57, No. 1The noradrenaline-containing innervation of the cochlear nucleus and the detection of signals in noiseBrain Research, Vol. 105, No. 3The release of acetylcholine from the cochlear nucleus upon stimulation of the crossed olivo-cochlear bundleNeuropharmacology, Vol. 13, No. 7The physiology of auditory frequency analysisProgress in Biophysics and Molecular Biology, Vol. 28Olivo-cochlear inhibition during physostigmine-induced activity in the pontine reticular formation in the decerebrate catExperimental Neurology, Vol. 40, No. 1Studies of peripheral gating in the auditory system of catsElectroencephalography and Clinical Neurophysiology, Vol. 32, No. 5Arousal effects on cochlear potentials: Investigation of a two-factor hypothesisBrain Research, Vol. 39, No. 1Efferent inhibition of afferent acoustic activity in the unanesthetized rabbitExperimental Neurology, Vol. 31, No. 3Effects of repetitive stimulation and state of arousal on cochlear potentialsExperimental Neurology, Vol. 29, No. 1Effects of ablations of temporal cortex upon speech sound discrimination in the monkeyExperimental Neurology, Vol. 24, No. 4 More from this issue > Volume 31Issue 1January 1968Pages 122-30 https://doi.org/10.1152/jn.1968.31.1.122PubMed4966613History Published online 1 January 1968 Published in print 1 January 1968 Metrics

Frequency discrimination in noise.

Frequency-discrimination performance is measured as a function of the ratio of signal energy to noise-power density (ε-η0) for several values of frequency separation at 250, 1000, and 4000 cps. Discrimination performance at all frequencies and all frequency separations increases with increasing ε-η0 until ε-η0 reaches 40 dB. No further increase in performance was apparent with a further increase of 40 dB in ε-η0.

Frequency Discrimination in Noise

The relation between frequency discrimination and the ratio of signal-energy to noise-power density (E/No) was investigated at three frequencies—250, 1000, and 4000 cps. On each trial of the experiment, two tones of equa energy were presented one after the other in a background of continuous white noise (32–dB spectrum level). The observers were required to judge whether the first or the second tone had been the higher-frequency tone. The higher-frequency tone was equally likely to precede or follow the lower-frequency tone. Discrimination performance for tones of different frequency separation (ΔF) was measured as the percentage of correct responses in 200 trials. Discrimination performance at all frequencies and all frequency separations increases with increasing E/No until E/No reaches 40 dB. No further increase in performance was apparent with a further increase in E/No of more than 40 dB. The limiting performance levels are not due to amplitude-limiting in the auditory system, since lowering the background-noise level has no effect on the ultimate performance limits. The implications of these data for some models of the auditory process are discussed. [Research supported in part by the National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare.]